1. Field of the invention
The present invention concerns an apparatus for processing a material web, e.g., a paper web, with a cylinder, e.g., a heatable cylinder, rotatable around its longitudinal axis, over which the material web is guided. An endless belt, made of elastic material, e.g., rubber, contacts the cylinder during operation and circulates in a same direction as the material web around an axis parallel to the axis of the cylinder. The belt runs around, and is guided by, three belt guide rolls, at least one of which is mounted movably to tension the belt. The present invention also concerns a process for processing the material web in the apparatus, and a process for replacing the belt.
2. Discussion of Background Information
Devices similar in general to the one described above are used, e.g., as compression devices in paper production machines to increase a load bearing capacity of the paper produced, which is necessary in the production of, e.g., bag paper. The rubber belt circulates at a speed which results in a speed differential at the line of contact with the cylinder of approximately 10 to 30% relative to the speed of travel of the paper.
Thus, belt replacement in such devices, which must be carried out approximately every 3 to 4 months, is problematic. In the known devices, at least one of the belt guide rolls tensioning the belt must be removed and suspended at an appropriate place so that the rubber belt can be released and removed from the device.
The present invention provides a device of the type generally discussed above, but which enables easier belt replacement.
In particular, the present invention relates to an apparatus that includes a belt guide roll located inside the belt that is pivotably hinged, between a tensioning position and a retracted position, on a fixed carrier, and a tensioning roll pivotably coupled, between a retracted position and a loading applying position, to a second fixed carrier, such that the tensioning roll is located outside of the belt to apply the load to the outside of the belt and between the pivotable belt guide roll and an adjacent belt guide roll.
The pivotable belt guide roll inside the belt and the pivotable tensioning roll provided outside the belt operate in coordination in the device according to the invention to tension the belt. For belt replacement, both rolls are pivoted into their retracted position. The belt is then free and can be removed from the device and replaced with a new belt.
Thus, in the device according to the invention, a belt change is possible without removing a roll. Accordingly, the belt change is simplified and accelerated. Moreover, the requirement of using special bearings which must be opened for the removal of a roll is eliminated. Instead, standard bearings may be used for all rolls and the costs of the device as a whole are thus reduced.
A further advantage of the device according to the invention is that it can be designed in a compact manner. Because of the coordinated operation of the two pivotable rolls inside and outside the belt, the necessary pivot zones of the two rolls are accordingly small. Moreover, the two pivot zones can partially overlap such that the space requirement as a whole is relatively small. This also has the advantageous result that a shorter belt length may be selected than in the above-noted known devices.
According to one embodiment of the invention, the belt guide rolls can be arranged on a common carrier. Thus, structural parts and structural space may be advantageously saved.
According to another embodiment of the invention, a regulator roll can be provided to regulate belt tension during operation. Thus, it is possible to compensate for fluctuations of belt tension occurring during operation and for elongation of the belt over time.
According to another embodiment of the invention, the tensioning roll can be coupled, e.g., to a support cross beam can be formed as a regulator roll. By this dual function of the tensioning roll, structural parts and structural space are saved, e.g., large regions of the belt can be kept free of structural parts.
The tensioning roll can preferably be arranged on a pivot arm, which is pivotable between the retracted position and the tensioned position, and the tensioning roll may be movable relative to the pivot arm to regulate belt tension, e.g., pivotable around an axis. Thus, a dual function of the tensioning roll for tensioning and regulating belt tension can be realized economically and with an uncomplicated design.
According to another embodiment of the invention, three belt guide rolls are provided, of which two are arranged at approximately a same height at a distance above the cylinder, and the third belt guide roll, which is the pivotable belt guide roll, can be arranged below and near the cylinder. This device has proved advantageous, e.g., to maintain access to the cylinder and the view of the line of contact between the belt and the cylinder free. Thus, the line of contact is highly visible and the cylinder can be removed laterally from the support without it being necessary to remove the fixed carrier bearing the belt guide rolls, which was one of the drawbacks of the above-mentioned devices.
According to another embodiment of the invention, the third belt guide roll can be arranged to the side of the cylinder in its tensioned position. This is also advantageous in terms of design to enable easy removal of the cylinder. In addition, the structural height of the device may be reduced, and the line of contact between belt and cylinder is highly visible from the opposite side.
According to another embodiment of the invention, the tensioning roll may be arranged on the side of the third belt guide roll facing away from the cylinder. This arrangement increases the compactness of the device. Moreover, access to the cylinder and the view of the line of contact between belt and cylinder are kept free.
To obtain a desired contact pressure between the belt and cylinder, in a further embodiment of the instant invention, a pressing rod can be provided inside the belt and can be adapted to press the belt against the cylinder during operation. Preferably, the pressing rod can be supported on the first carrier so that a separate structural element is not necessary.
According to another embodiment of the invention, at least one cooling spray tube with spray nozzles may be provided for spraying cooling fluid on the belt, and the tube may be located to the side and above the belt. Overheating of the belt can prevented with the cooling spray tube, and the arrangement to the side and above the belt has the advantage that removal and replacement of the belt is possible without removing the cooling spray tube. Thus, the supply and discharge lines of the cooling spray tube can also remain connected during belt replacement.
The compact arrangement of the device and keeping large regions of the belt free of structural parts has the advantage that repair devices for the belt may be used while the belt is installed. Thus, without removal of the belt, vulcanizing plates can be applied to the belt to postvulcanize the belt, if need be.
The present invention is directed to an apparatus for processing a material web that includes a rotatable cylinder, in which the material web is guided over the rotatable cylinder, a first fixed carrier, and at least three belt guide rolls, in which one of the at least three guide belts is pivotably coupled to the fixed carrier. An endless belt is mounted on and guided by the at least three belt guide rolls, such that the endless belt is guided over the rotatable cylinder in a same direction as the material web, and the pivotably coupled belt guide roll is pivotably positionable between a tensioning position and a retracted position relative to the endless belt. A second fixed carrier is provided and a tensioning roll is positioned outside of the endless belt and pivotably coupled to the second fixed carrier, so that the tensioning roll is pivotably positionable between a retracted position and a loading position of the endless belt. The tensioning roll is farther positioned between the pivotably coupled belt guide roll and an adjacent belt guide roll.
According to a feature of the instant invention, the at least three belt guide rolls can be arranged on a common carrier.
In accordance with another feature of the invention, the tensioning roll can be coupled to a support cross beam.
Further, the belt travel is regulated during operation. The tensioning roll can be adapted as a regulating roll to regulate belt travel during operation. A tensioning roll pivot arm may be coupled to the tensioning roll to pivotably position the tensioning roll between the retracted and loading positions, such that the tensioning roll is pivotably coupled to the tensioning roll pivot arm to regulate belt tension by pivoting movement relative to the tensioning roll pivot arm.
Two of the at least three belt guide rolls can be arranged at approximately a same height and at a distance above the rotatable cylinder, and the pivotably coupled belt guide roll may be positioned below the two belt guide rolls and near the rotatable cylinder. The pivotably coupled belt guide roll can be positioned beside the cylinder in the tensioned position and near the first fixed carrier in the retracted position. The tensioning roll can be positioned on a side of the pivotably coupled belt guide roll facing away from the rotatable cylinder.
According to another feature of the present invention, the apparatus can further include a cylinder and a belt pressure rod coupled to the cylinder. The cylinder and the belt pressure rod may be located inside the endless belt, and the belt pressure rod can be adapted to press the endless belt against the rotatable cylinder during operation. The belt pressure rod can be supported on the first fixed carrier.
In accordance with still another feature of the invention, the apparatus can further include at least one cooling spray tube with spray nozzles for spraying cooling fluid on the endless belt. The at least one cooling spray tube can be arranged to a side and above the endless belt.
According to a further feature of the instant invention, the apparatus forms a compression device of a paper production system.
Further, the apparatus can be positioned in a central region of a dryer section of a paper production system.
Moreover, the endless belt can be circulated so that a speed differential of between approximately 10 to 30% occurs between a travel speed of the endless belt and a travel speed of the material web at a line of contact with the rotatable cylinder.
In accordance with the features of the invention, the rotatable cylinder can include a heatable cylinder, the material web can include a paper web, e.g., a bag paper web, and the endless belt can include an elastic, e.g., rubber, belt.
The present invention is directed to a process of treating a material web in an apparatus that includes a rotatable cylinder, a first fixed carrier, at least three belt guide rolls, in which one of the at least three guide belts is pivotably coupled to the fixed carrier, an endless belt mounted on and guided by the at least three belt guide rolls, a second fixed carrier, a tensioning roll positioned outside of the endless belt, pivotably coupled to the second fixed carrier, and positioned between the pivotably coupled belt guide roll and an adjacent belt guide roll relative to the endless belt. The process includes guiding the material web between the endless belt and the rotatable cylinder in a same direction as the endless belt, and pressing the material web against the rotatable cylinder with the endless belt.
According to a feature of the instant invention, the process can further include regulating a belt tension in the endless belt with the tensioning roll.
In accordance with another feature of the invention, the process can further include creating a speed differential of between approximately 10 to 30% between a travel speed of the endless belt and a travel speed of the material web at a line of contact with the rotatable cylinder.
The invention is directed to a process of replacing an endless belt in an apparatus that includes a rotatable cylinder, a first fixed carrier, at least three belt guide rolls, in which one of the at least three guide belts is pivotably coupled to the fixed carrier, an endless belt mounted on and guided by the at least three belt guide rolls, a second fixed carrier, a tensioning roll positioned outside of the endless belt, pivotably coupled to the second fixed carrier, and positioned between the pivotably coupled belt guide roll and an adjacent belt guide roll relative to the endless belt. The process includes pivotably moving the tensioning roll from a loading position to a retracted position, such that the endless belt is released by the tensioning roll, pivotably moving the pivotably coupled belt guide roll from a tensioning position to a retracted position relative to the endless belt, such that the endless belt is released by the pivotably coupled belt guide roll, lifting the belt from the remaining guide rolls and removing the endless belt. The process also includes placing a new endless belt on the remaining guide rolls, pivotably moving the pivotably coupled belt guide roll from the retracted position to the tensioning position, and pivotably moving the tensioning roll from the retracted position to the loading position.
In accordance with a feature of the invention, the apparatus can further include a belt pressure rod coupled to a cylinder located inside the endless belt, and the process can further include, before lifting the belt, from the remaining rolls, retracting the belt pressure rod from the endless belt, and, after placing the new endless belt on the remaining guide rolls, pressing the endless belt against the rotatable cylinder with the belt pressure rod.
The present invention is directed to a dryer section for processing a material web. The dryer section includes a compression device that includes a rotatable cylinder, where the material web is guided over the rotatable cylinder, a first fixed carrier, and at least three belt guide rolls, in which one of the at least three guide belts is pivotably coupled to the fixed carrier. An elastic endless belt is mounted on and guided by the at least three belt guide rolls, so that the endless belt is guided over the rotatable cylinder in a same direction as the material web, and the pivotably coupled belt guide roll is pivotably positionable between a tensioning position and a retracted position relative to the endless belt. A second fixed carrier is provided and a tensioning roll is positioned outside of the endless belt and pivotably coupled to the second fixed carrier, such that the tensioning roll is pivotably positionable between a retracted position and a loading position loading of the endless belt. The tensioning roll is further positioned between the pivotably coupled belt guide roll and an adjacent belt guide roll.
According to a further feature of the invention, the tensioning roll includes a tensioning roll pivot arm coupled to the tensioning roll to pivotably position the tensioning roll between the retracted and loading positions, and a positioning device to pivotably move the tensioning roll relative to the tensioning roll pivot arm. In this manner, the tensioning roll is adapted as a regulating roll to regulate belt travel during operation. The at least three belt guide rolls can be arranged on a common carrier, and two of the at least three belt guide rolls may be arranged at approximately a same height and at a distance above the rotatable cylinder, and the pivotably coupled belt guide roll can be positioned below the two belt guide rolls and near the rotatable cylinder. The tensioning roll may be positioned on a side of the pivotably coupled belt guide roll facing away from the rotatable cylinder. Further, a belt pressure rod can be located inside the endless belt and adapted to press the endless belt against the rotatable cylinder during operation. The belt pressure rod may be supported on the first fixed carrier. Moreover, the endless belt can be circulated so that a speed differential of between approximately 10 to 30% occurs between a travel speed of the endless belt and a travel speed of the material web at a line of contact with the rotatable cylinder.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.